Talk:Type 91 Armor Piercing Shell/@comment-3213090-20151203040927/@comment-26486243-20151218165935
If we assume your battleship is at firepower cap so that the additional FP from this isn't a factor: *Main Gun + Main Gun + Radar + Seaplane **120% dmg * 2 **Otherwise 100% dmg * 1 *Main Gun + Main Gun + AP Shell + Seaplane: **162% dmg * 1 **Otherwise 130% dmg * 2 **Otherwise 108% dmg * 1 The case where AP Shell becomes a liability relative to not having it at all applies only when comparing 162% dmg vs 120% dmg * 2. *When enemy armor roll = 243, AP shell cut-in does 0 damage. *When enemy armor roll = 180, Double attack does 0 damage. *243-x > 2(180-x) *243-x > 360 - 2x *x > 117 Therefore, it is a benefit in the highest-frequency trigger when the enemy rolls an armor value greater than 117. It is a liability in the highest-frequency trigger when the enemy rolls an armor value of 116 or low. However, at armor value 117, the damage dealt through both attack types is 126. Therefore, for it to ever be a better idea to carry a radar instead of an AP shell in pure damage numbers, you need to hit something that consistently rolls an armor value lower than 117 and yet has much more than 126 health. Since the maximum armor roll is 130% of base armor, the armor value to shoot for is 91. Any target with > 126 health and < 91 armor will be better sunk with a radar instead of an AP shell. The list of targets fulfilling this requirement are as follows: *Wa-Class Flagship Transport *Anchorage Princess/Demon *Armored Carrier Princess/Demon *Southern Demon *Southern War Demon. Against all other boss-class targets the AP shell is superior, and against fodder it doesn't matter whichever you use since you'll sink it anyway. We are, however, ignoring completely the fact that AP shells also trigger a higher damage double attack at a lower rate, and that even single attacks hit harder when AP shells are equipped. As for single digit APCI damage, there are only two explanations for this: *You're fighting an absurdly high armor boss (particularly installations), where the armor roll is very slightly less than to the APCI damage value. Double attack seems to do better because its damage is so greatly inferior that it does scratch damage instead, and double scratch damage against a 300 HP target can do 57 damage, far more than a 243 damage attack will do against a 238 armor roll. **Every target where this is true is either an installation boss or is meant to be attacked using cut-in attacks at night. If installation, you should be using Type 3 shells at night, not AP shells. If it's meant to be attacked using cut-in attacks, this is a job for your other ships to handle, not your BB... unless her name is Bismarck drei, and she has 70 luck. *Your attacks were critical-evaded, which makes any attack, regardless of attack power, deal only 6-14% damage of a target's current HP value. The first is more likely, as the second occurrence is low-probability - having it build an impression is extremely unlikely unless you either have improbably bad luck, or your perception is subject to uncommonly high levels of cognitive bias. Read Combat for more details. The whole thing. Partial knowledge is worse than none at all as it reduces someone's openness to viewing reality.